The machinability of a gamma titanium aluminide intermetallic

Hood, Richard (2010). The machinability of a gamma titanium aluminide intermetallic. University of Birmingham. Ph.D.

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Abstract

The work reported details the machinability of the gamma titanium aluminide intermetallic (-TiAl) Ti-45Al-8Nb-0.2C currently under evaluation to be the material of choice for blades and stators in the intermediate compressor (IP) and low pressure (LP) turbine sections of an aeroengine due to the alloys high temperature (~800C) and low weight properties. Following a literature review, the thesis details the results from two phases of experimental work. The first focused on high speed milling trials using coated tungsten carbide ball nose end mills with various operating parameters whilst the second phase provided an assessment of intermittent dress creep feed grinding using both conventional (SiC) and superabrasive (diamond and CBN) wheels with free jet nozzles. Benchmarking of the -TiAl alloy against other -TiAl (Ti-45Al-2Mn-2Nb +0.8%vol. TiB2), burn resistant and conventional titanium (Ti-6Al-4V) alloys was also performed. Full and fractional factorial (Taguchi) experimental designs were employed to identify the effect of key operating factors and levels on output measures (tool life/wheel wear, forces, power, and workpiece surface roughness). Taguchi main effect plots are detailed, together with Analysis of Variance (ANOVA) data and percentage contribution ratio (PCR) values. In addition, workpiece surface integrity evaluation including assessment of microstructure and microhardness is also presented..

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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